The present invention relates to a power supply start up circuit and more particularly to a power supply start up circuit designed to inhibit power losses by dissipation therefrom.
Switching power supplies of various topologies are used to provide a regulated output voltage (Vreg) from an unregulated or regulated input voltage (Vin).
As discussed in greater detail below, prior art switching power supplies suffer from prolonged or erratic start-up times as a result of the time constraints in standard prior art resistor capacitor startup circuits.
Also, prior art switching power supplies are prone to continuous power dissipation in the bleeder resistor of the standard resistor capacitor startup circuit during normal operation.
Furthermore, prior art switching power supplies suffer from excessive heating of circuit components during overload or short circuit conditions where such heating is as a result of the output being cycled on and off at a rate determined principally by the time constraints in the standard resistor capacitor startup circuit.